U352CHigh Voltage System Interlock Circuit H High
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U352C reports an excessive reading on loop H. Whether that points to foreign voltage or to a break depends on the quantity the controller evaluates. If it reads voltage, a wire touching 12 V is the usual reason. If it works out the loop's resistance, as Lear's tester patent does, a value beyond the maximum is treated as open and one under the minimum as shorted, so high may mean corrosion or a loose terminal. The service data of the specific vehicle settles which reading applies; for U352C no maker publishes it. Measure loop H resistance with every plug latched and compare it with a sound loop of the same vehicle.
- What you may notice
- No ready mode, high-voltage warning
- Fault sometimes disappears after moving connectors
- Likely causes
- PossibleLoop H wire in contact with a 12 V supply
- PossibleCorroded or loose terminal raising loop H resistance
- RareLoop source stuck on in the controller
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.